The reference/example projects (`references/`) now live in their own
repo, https://github.com/triggerdotdev/references, so their heavy,
frequently-changing dependencies are no longer part of this repo's
lockfile and tooling. This removes them here and repoints everything
that referenced them.
- Deletes `references/`; updates the pnpm workspace + lockfile.
- Clears the references-only CI rules and `.vscode` configs.
- Repoints the docs (contributor/agent + one public page) to the new
repo.
- `seed.mts` keeps the local-dev projects (hello-world, d3-chat,
realtime-streams).